Food products produced for public consumption are often enhanced by adding nutritional or other types of supplements in order to improve their nutritional properties, commonly called fortification. Fortification is typically done with nutrients that are not adequately consumed in the diet. Thus, the fortified food provides an additional source of the needed nutrient, and improves the nutritional quality of the consumer's diet.
Magnesium is an essential nutrient. Among other things, it is a key bone health nutrient; approximately 60% of magnesium is stored in bone. However, large human population segments do not consume the recommended levels of magnesium in their diet. As a result, fortification of foods with magnesium is desirable. However, fortification with minerals like magnesium is often problematic in the food due to its high level of reactivity in foods. Challenges with magnesium fortification can include color, flavor, and texture changes and processing issues.
In general, nutrient fortification of foods is often achieved by blending the desired nutrient into the food product while it is being produced. There are many examples of fortification in the food supply. A common example is the fortification of milk with vitamin A, which is typically blended into the milk during processing. Other examples include the fortification of milk with calcium phosphates as disclosed in U.S. Patent Appln. Publication No. 2003/0165597, or the fortification of unripened dairy products such as skim milk and yogurt with combinations of dicalcium phosphate and magnesium phosphate as disclosed in U.S. Pat. No. 6,039,978, or drinkable yogurts as described in Food Product Design, “Pumped-Up Dairy”, October 2003.
Process cheese is made by heating natural cheese with emulsifiers. The emulsifiers solubilize the proteins so they do not precipitate as a result of the heat treatment. The emulsification of the dairy proteins is a sensitive balance of ion association with the protein. With magnesium fortification, one would expect that the magnesium would be added with the cheese and other ingredients and the mixture heated. However, when minerals like magnesium are added to process cheese for fortification, they can disrupt the ionic balance and often cause emulsification issues including texture defects like softening or curdling/separation. Further, process cheese contains other components that may react with the minerals over shelf life. For example, mineral-phosphate crystals can form over shelf life.
The prior art suggests means to overcome these issues. For example, divalent mineral fortification of milk was assisted by phosphates in the U.S. Patent Application Publication No. 2003/0165597. They were able to add soluble forms of calcium into the beverage prior to the addition of phosphates and keep the pH between 6.5 and 7.5. This was shown to not be feasible for magnesium in process cheese since the ionic exchange is more complex and requires a lower pH for stability.
As generally disclosed in U.S. Pat. Nos. 6,090,417, 6,326,038, and 6,426,102 B1, it is also known to fortify a cheese with certain vitamins or other nutritional supplements by first shredding the cheese to accept the fortification followed by a blending (e.g., tumbling) of the cheese shreds and fortifying additives, and then compressing (without melting) the coated cheese shreds back into a homogenous mass. U.S. Patent Application Publication No. 2003/0021873 also discloses a similar method of fortifying a shredded cheese with a calcium anti-caking agent.
Fortification methods that shred and recombine cheese have the shortcoming that significant additional processing steps are required for the cheese to receive the coating (i.e., shredding and blending), and to finish the product (i.e., compressing into a final form). The additional processing steps increase manufacturing complexity and costs. Also, coating particles tend to loosen and flake or dust off from the cheese shreds as coated by the prior methods, creating visible detritus in the food packages and/or interfere with package sealing operations. Also, some vitamins and minerals may adversely impact functionality and/or organoleptic properties of foods, and/or may be counter-productive to improving the beneficial health effects to foods if introduced in excessively large amounts relative to the food mass.
In addition to nutrient content, flavor is key to consumer acceptance of process cheese, and salty flavor has proven to drive some of that flavor and acceptability. Conventional process cheeses have relied upon sodium salts to impart saltiness, namely sodium chloride. However, sodium salt use has its limits due to nutritional and health concerns. To reduce sodium content of foods, potassium salts have been used as sodium salt substitutes. However, potassium salts have their drawbacks, as they tend to impart bitter flavors to the salted foods. To overcome the drawbacks of potassium salts, other additives are commonly used in conjunction with such potassium salts. Magnesium is among the options that can be used. Magnesium phosphates have been described as useful to mask the bitterness of potassium and chloride salts. Magnesium citrate may aid in flavor delivery. And magnesium can be included since it has important health functions. U.S. Pat. No. 4,471,002 describes a seasoning mix that can be used to flavor foods with cheddar cheese flavors. Magnesium salts are included in the mixture, magnesium phosphate being an option. The composition requires lactate, glycollate, magnesium, phosphate, sodium, potassium, chloride, carbonate, glutamate, and calcium. EP0 Patent No. 190521B1 describes the use of sea salt to make a low-sodium natural cheese, by using during salting for driving out water from the curd. Sea salt contains magnesium chloride, sodium chloride, potassium chloride, magnesium sulfate and magnesium oxide. U.S. Patent Appln. Publication No. 2004/0224076A1 describes a salt substitute composition that includes potassium chloride, sodium chloride, calcium salt, and magnesium. Magnesium was included to deliver magnesium to the diet for health benefits, while magnesium citrate was used as a flavor-enhancing agent, and magnesium carbonate for anti-agglomerating effects. Magnesium phosphate is discussed as a form of magnesium that can be used. U.S. Pat. No. 4,473,595 describes a salt substitute composition of sodium chloride, potassium chloride, magnesium sulfate or magnesium chloride. This composition was found to have high saltiness and low bitterness—magnesium sulfate serving as a bitterness masking agent. U.S. Pat. No. 4,243,691 describes a salt substitute containing nucleotides, amino acids, sugar, potassium phosphate, potassium chloride. Potassium phosphate used to mask the bitterness of sodium chloride and has some mouthwatering and astringency to it. U.S. Pat. No. 6,541,050B1 describes a salt enhancing composition with potassium chloride as the main ingredient and a sulfate salt used to mask the off-notes of the potassium chloride. U.S. Pat. No. 4,931,305 describes using a composition of magnesium sulfate, potassium chloride, sodium chloride and acidic amino acids as a salt substitute. The magnesium component required it be soluble and it was proposed that acidic components increase salty impact. U.S. Pat. No. 4,963,387 describes a salt substitute comprising whey minerals used with alkali metal salts (potassium and sodium). Optionally, the addition of calcium and magnesium salts can be included.
Prior to the present invention, a need has existed for methods that introduce nutritional supplements, particularly magnesium supplements, into process cheese products while providing cheeses that retain their flavor, texture, mouthfeel, and shelf stability. There further remains a need to provide process cheese products fortified with any of a broad range of nutritional supplements. The present invention fulfils these and other needs.